The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Motor vehicle engines produce torsional vibration that is undesirable to transmit through the powertrain and driveline to the motor vehicle. Typically, a torsional isolator or damper is used to isolate or reduce the torsional vibration transmitted from the engine to the transmission. The torsional isolator can be placed proximate a torque converter between a torque converter lock up clutch and an input shaft of the transmission. Known torsional dampers use one or more springs to store energy and are used to dampen an energy transfer path between the engine and the transmission. However, in certain powertrain configurations the torsional damper is insufficient to isolate the torsional vibrations. For example, in engines with rolling cylinder deactivation strategy, an increase in vibrational magnitude and a decrease in vibrational frequency occur at lower engine operating speeds and frequencies, which known single size spring design vibration dampers are insufficient to isolate within the design space, thereby requiring improvement over known vibration dampers.
Accordingly, there is room in the art for a powertrain having a vibration damper that reduces torsional vibration over a broader range of vibrational frequencies.